KUALA LUMPUR, March 4 ― One of the most baffling aviation mysteries ever seems no closer to being solved as the first anniversary of Malaysia Airlines Flight MH370's disappearance approaches on March 8.

Following is a timeline of major developments in the disappearance of the Boeing 777 and its 239 passengers and crew:

A Malaysian Maritime Enforcement Agency pilot studies the map on board a Japan Coast Guard Gulfstream V Jet aircraft, as they search for the missing Malaysia AirlinesMH370 plane over the waters of the South China Sea. ― File pic

Saturday March 8

― Flight 370 departs Kuala Lumpur at 12.41am, bound for Beijing. It vanishes from Malaysian civilian radar at 1.30am, just before passing to Vietnamese air traffic control. It appears on military radar until 2.15am, but Malaysia's air force takes no action.

― Vietnam launches a search operation that expands into a multinational hunt in the South China Sea.

― Two passengers who were travelling on stolen EU passports spark speculation of a terrorist attack, but are revealed to be merely suspected Iranian illegal immigrants. Malaysian police later say background checks of all on board produced no red flags.

Pictures of aircraft engineer Mohd Khairul Amri Selamat who was on board the missing Malaysia Airlines Flight MH370, are seen in Putrajaya March 16, 2014. — Reuters pic

Sunday March 9

― Malaysia's air force chief says the plane may have turned back towards Kuala Lumpur for no apparent reason, citing radar data. In the coming days, the search area expands to the west of the Malaysian peninsula and the air force confirms the blip on its radar was indeed MH370.

Family members of passengers aboard the missing Malaysia Airlines Flight MH370 react as they watch Malaysia's Prime Minister Datuk Seri Najib Razak speak on a television screen at a hotel in Beijing, March 15, 2014. — Reuters pic

Friday March 14

― The hunt spreads far south to the Indian Ocean after the White House cites “new information” that the jet may have flown on after losing contact.

A family member of a passenger on board the missing Malaysian Airlines flight MH370 cries as he watches a message board dedicated to passengers onboard the missing plane at a hotel in Beijing March 20, 2014. — Reuters pic

Saturday March 15

― At a dramatic news conference, Malaysian Prime Minister Datuk Seri Najib Razak says the plane appears to have been flown deliberately for hours, veering sharply off-route at roughly the same time that its communications system and transponder were manually switched off.

― Satellite data suggests the jet's last known location was somewhere along one of two huge arcs stretching north into Central Asia and south into the Indian Ocean. The South China Sea search is called off.

Family members of passengers of Malaysia Airlines flight MH370 leave a rest area after a morning meeting at Lido Hotel in Beijing, March 12, 2014. — Reuters pic

Sunday March 16

― With more than two dozen countries now involved in the search, suspicions focus on the pilot and co-pilot, both Malaysians. FBI experts examine the hard drive on a flight simulator in Captain Zaharie Ahmad Shah's home, but find nothing suspicious.

Construction site workers light candles to pray for passengers of the missing flight MH370, in Wuhan, Hubei province, March 13, 2014. — Reuters pic

Thursday March 20

― Australia says satellites photographed two large objects in the remote southern Indian Ocean, but the flotsam proves to be another in a series of a false alarms.

Monday March 24

― Najib announces “with deep sadness and regret” that MH370 is presumed to have crashed in the Indian Ocean, citing new analysis of satellite data.

The next day in Beijing, emotional Chinese relatives of passengers scuffle with guards outside the Malaysian embassy, demanding answers.

Datuk Seri Najib Razak (centre) addresses reporters about the missing Malaysia Airlines flight MH370, as Transport Minister Hishammuddin Hussein (left) and Department of Civil Aviation's Director General Azharuddin Abdul Rahman (right) stand by him. ― File pic

Monday March 31

― Malaysia releases a transcript of all the pilots' radio communications, but it sheds little light.

Friday April 4

― A US-supplied “black box” detector begins scanning the suspected crash zone, with the clock ticking on the one-month battery life of their locator beacons.

A helicopter takes off from Jinggangshan warship to search the waters suspected to be the site of the missing Beijing-bound Malaysia Airlines flight MH370 in this March 11, 2014 photo courtesy of China News Service. — Reuters pic

Saturday April 5

― A Chinese search ship detects an underwater “pulse signal” in the Indian Ocean. More “pings” are detected by other vessels in subsequent days, but they cease before they are pinpointed. Some experts later express doubt they were related to MH370.

Phoenix International workers inspect the Bluefin 21 autonomous underwater vehicle (AUV) before deployment in the southern Indian Ocean to look for the missing Malaysia Airlines flight MH370, April 15, 2014. — Reuters pic

Monday April 14

― Halting the search for underwater signals, Australia deploys an American deep-sea drone to scan the seabed for debris near the ping sites. It ultimately finds nothing.

Monday April 28

― Australia announces the search area will be expanded across a huge swathe of ocean. The focus shifts for several months to mapping the uncharted seafloor before searching can resume.

A relative of a passenger aboard Malaysia Airlines MH370 prays in front of a message board dedicated for the passengers at the Lido Hotel in Beijing April 1, 2014. — Reuters pic

Tuesday May 27

― After weeks of pressure from families, Malaysia releases raw satellite data used to determine the search zone. Relatives say crucial data was omitted.

Monday October 6

― A Malaysia-contracted vessel resumes the sonar search of the seabed for debris. Three specialised Dutch search ships eventually join an effort expected to wrap up in May 2015.

Staff at satellite communications company Inmarsat work in front of a screen showing subscribers using their service throughout the world, at their headquarters in London March 25, 2014. — Reuters pic

Thursday January 29

― Malaysia's government declares MH370's passengers and crew “presumed dead”, angering next of kin who demand proof.

Wednesday February 4

― Prompted by the MH370 mystery, a global aviation summit in Montreal backs plans to require real-time tracking of any airliners that encounter distress, starting in 2016.

Wednesday February 25

― Australian authorities say vessels have completed scanning about 40 percent of a 60,000-square-kilometre (23,166-sq-mile) “priority search area” ― and found nothing.

Wang Run Xiang, 58, the mother of a passenger aboard missing Malaysia Airlines Flight MH370, holds a picture of her grandson whose father was aboard the plane in Kuala Lumpur February 12, 2015. — Reuters pic

Sunday March 1

― Australia says it is conducting trials with Malaysia and Indonesia of a system that increases the frequency with which planes are tracked over remote oceans, to avoid an MH370 recurrence. ― AFP